Bosch 13056 Oxygen Sensor - Downstream

Bosch Oxygen Sensor 13056 for Downstream Applications

Bosch Engineered Oxygen Sensor 13056 is a specific-fit, narrow-band heated oxygen sensor built for downstream emission control applications. It delivers air-fuel-ratio feedback to the ECU for stable combustion control and lower emissions in everyday driving.

Compatible With 1995-2002 Toyota Corolla, 1995-1997 Toyota Avalon, 1995-1997 Geo Prizm, and 1998-2002 Chevrolet Prizm, this Bosch oxygen sensor is a direct replacement for the listed downstream positions.

Key Features

• Bosch Engineered Oxygen Sensor line with OE-focused design
• Part number 13056
• Narrow-band heated oxygen sensor for downstream use
• Specific fit with included wiring harness
• 4-wire configuration with blade terminals and rectangular male connector
• Threaded mounting, 18 mm thread size, 22 mm hex size
• Metal housing with high-temperature-resistant construction

Detailed Description

Bosch 13056 uses a switching-type narrow-band design to report exhaust oxygen content to the engine control unit. Bosch developed this sensor family from its early oxygen sensor work and later planar narrowband technology, which supports faster light-off and quicker closed-loop operation. The result is consistent signal response under heat, vibration, and normal road use.

This part is a direct-fit downstream oxygen sensor for Toyota Corolla, Toyota Avalon, Geo Prizm, and Chevrolet Prizm applications listed below. It is a practical replacement when the original sensor has aged, slowed response, or triggered emissions-related fault codes. This part cross-references 8946502030 and 8946512390 for the same application.

What It Helps Address

• Check engine light related to oxygen sensor performance
• Rich or lean fuel trim readings from a worn downstream sensor
• Slow sensor response during closed-loop operation
• Emissions test failures tied to oxygen sensor output
• Rough combustion control caused by inaccurate exhaust feedback

Installation Notes and Tips

Verify the connector shape, 4-wire layout, and threaded mounting before installation. The sensor is listed for downstream positions only, so confirm the vehicle’s sensor location before ordering. Inspect the harness routing and exhaust threads for heat damage, corrosion, or cross-threading before tightening the replacement sensor.

Fits 1995-2002 Toyota Corolla, downstream. Fits 1995-1997 Toyota Avalon, downstream. Fits 1995-1997 Geo Prizm, downstream. Fits 1998-2002 Chevrolet Prizm, downstream.

Quality Assurance

Bosch backs this oxygen sensor with more than five decades of OE development experience. The design reflects Bosch’s long-running focus on accurate sensor output, durable heater control, and materials suited for demanding exhaust temperatures and vibration exposure.